Dispersion-Corrected Density Functional Tighiting Binding Modeling of the Natural Metastable Twin Boundary of Organic Energetic Materials: Beta-Octahydro-1,3,5,7-Tetranitro-1,3,5,7-Tetrazocine

A comparative study of the geometries and electronic properties of twin boundary (TB), as a typical planar defect, in crystalline β-boctahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (β-HMX) was conducted by using self-consistent charge density functional tight binding with dispersion corrections (SCC-DFTB-D). The possible twinned structures were predicted and compared with many experiments. The calculated electronic properties of the proposed TBs showed that the interface of twin boundary were more active than the bulk region. The TBs grown along the (001) plane was shown to be more energetically stable than other TBs along (101) and (10-1) plane. The most stable TB structure was compared with available experimental results. The formed TB in the ideal bulk increases internal instability and thus increases the sensitivities of the real materials to the external stimuli.

Research Interests: theoretical study of crystal defects of organic materials.

Teaching Interests: molecular simulation methods.